We've been waiting for the Israelis for a long time," said Mansour Khoury as he stood at the door of his women's boutique in this mountain village east of Beirut. "We'd like to finish with this war, and we're happy to see them."

"But they don't come to my restaurant because it's Arab," complained Kalal Madah, the owner of the cafe across the street.

Here in Lebanon's "little Switzerland," an area of prospering summer resorts and winter sports facilities in the country's Christian heartland, the Israeli invasion generally has been welcomed. As in other Christian-held areas untouched by the current fighting between the Israelis and the Palestinians and Syrians, the people here hope that the invasion somehow will end the intermittent strife that has killed perhaps 100,000 Lebanese since 1975.

But there are already signs of some nervousness among the Christians about how long the Israelis intend to stay. It is a question raised repeatedly by those who remember how the embattled Christians joyfully greeted the Syrian invasion in 1976, when Damascus stepped in to save Christian militias from defeat by an alliance of Palestinians and Lebanese leftists.

Two years later, the same Syrian Army unleashed its heavy artillery on Christian residential areas of East Beirut in an effort to curb the growing power of the Christian militias.

Such reservations were reflected by the comment of life-insurance salesman Issa Bahre, as he stood on the ridge here gazing through binoculars toward a distant hill at flashes of tank fire and billowing smoke from battles between Israeli and Syrian forces yesterday.

"We don't need any strangers in Lebanon," he said shortly when asked how he felt about the Israeli presence. Bahre said he had moved to Broumana last year when Palestinian gunmen took over his house in predominantly Moslem West Beirut.

In any case, Israeli soldiers and officers now come here often from a camp a few miles down the road toward Beirut. The officers come mostly to eat in the town's fine restaurants, and troops on patrol can be seen bargaining for such items as roasted chickens at streetside stalls.

Many Lebanese merchants here now accept shekels, the Israeli currency, and change them back into Lebanese pounds at mobile banks in the form of small vans that circulate in the Israeli-held areas.

Aside from the occasional Israeli military checkpoint on roads into the mountains east of Beirut, other signs of the Israeli presence are road markers spray-painted in Hebrew along routes traveled by the Israeli troops. One such sign is posted on the median strip a few hundred yards from the main crossing point into West Beirut, warning the errant Israeli driver away from the zone controlled by Palestinian guerrillas and Moslem leftist militia.

In a well-appointed, air-conditioned office in mainly Christian East Beirut sits the spokesman of the "Lebanese Forces," otherwise known as the militia of the Maronite Christian, right-wing Phalange Party. Ensconced behind a large, wooden desk of modern design, he occasionally takes calls on a battery of complicated telephones on his left. At the end of the office to his right is a video recorder and television set. On the walls are pictures of Bashir Gemayel, the son of the Phalange Party's founder and now its undisputed military leader.

According to the spokesman, who does not want to be named, the militia intends to stay out of the current fighting between the Israelis and their Palestinian and Syrian foes, despite what amounts to a tacit alliance with Jerusalem.

"We will not be involved on a military level," he says. "We are trying to profit from this situation on a political level only."

At the least, the Phalangists see the invasion as an opportunity to restore the authority of the Christian-led Lebanese state over the Moslem militia ruling West Beirut.

Despite the Phalangists' claims that there is no military cooperation with the Israelis, small indications of the close relationship between the two sides are emerging as the Israelis settle in for what some Lebanese believe may be a long stay.

For years, Phalangist militia have been receiving military training in Israel, which has also supplied heavy weapons and other equipment to the Christians.

The supplies include Israeli uniforms, which can be seen in abundance now in the Christian-held areas, and not just on Israelis. Phalangist militiamen at checkpoints in East Beirut often can be seen in Israeli uniforms, including the distinctive cap, but with the Lebanese cedar-tree symbol over their pockets instead of Hebrew lettering.

From a distance, it is thus sometimes difficult to tell Israeli troops from Christian militia, but the Lebanese generally seem to have better tailors.

The Phalangists also have been helping out the Israelis by setting up checkpoints near Israeli military encampments and providing escort officers for visiting Israeli journalists and Israeli commanders.

Asked about the Phalangist attitude toward the Israelis, the militia spokesman said that "as long as the Israelis behave correctly" they would be no trouble for the Christians.

"Lebanon is a country with a very old tradition of hospitality," he added with a wry smile.