Visitors were welcome today, but the car had to be left outside because the driveway was strewn with butterfly-winged, silver cones each containing a sphere slightly larger than a squash ball and equipped with a plunger detonator.

To weapons buffs the objects littering the grounds at the Armenian sanitarium in this mountain town 16 miles southeast of Beirut are known as CBUs, short for cluster bomb units.

One canister contains hundreds of these bomblets. The canister breaks open when dropped from an airplane and explodes before hitting the ground, spraying the exploding antipersonnel devices over an area the size of a football field.

When the Israelis dropped CBUs on the Palestinian refugee camp at Rashidiyeh during their 1978 invasion of southern Lebanon, the U.S. Congress considered holding up further arms supplies to the Jewish state on the ground that they had been meant for defensive use only.

Lebanese intelligence sources said that the Israelis also dropped CBUs yesterday on Bourj el Brajneh, the Palestinian refugee camp closest to Beirut's airport.

The sanitarium here was damaged when the Israelis used the weapons to back up their armor's lightning drive through the Chouf region, which almost dislodged the Syrians from their vital communications link that is the Beirut-Damascus highway just three miles farther north.

Here, in the Lebanon range that dominates the rich Bekaa Valley to the east adjoining Syria, the Israelis took no chances.

In the heat of a major tank, artillery and later air battle, the Israelis appear to have used every weapon at their disposal. There was no evidence that the destruction of the sanitarium was anything more than an accident of war. There were also confused reports of Syrian soldiers being in the area of the sanitarium during the fighting.

The CBUs gouged holes in the driveway at the sanitarium that, since 1937, has cared for tuberculosis patients and now houses aged and often bedridden patients of Lebanon's many creeds and communities as well.

No one was killed, although three villagers were wounded severely later when they picked up unexploded CBUs out of curiosity.

Nor were the CBUs the Israelis' only calling card here. Blown-out windows and doors, smashed equipment, a punctured water tower, gaping holes in the roof and walls and collapsed concrete slabs littered the hospital. That the sanitarium building survived so well bore testimony to the ability of the reinforced concrete in the three-story building to withstand the explosives hurled onto it by Israeli heavy artillery.

The red cross painted on the hospital roof and a small Red Cross flag flying from the third floor should have been visible at the time the Israelis opened fire, according to hospital administrator Gabriel Mikalian.

But he also noted that at one point during the air and artillery bombardment in this front-line town, Syrian troops had taken shelter overnight under the trees in the garden near the adjoining research center.

Mikalian said he could not remember just when the Syrians had been there. He and the other staff and the 146 patients seemed still confused and battered by the travail that the sanitarium had endured.

During the bombardment, which went on for about four days, the staff had moved most of the patients to the safety of the basement.

The three wounded patients were all among the bedridden who could not move themselves and whom the staff did not rescue for days because they were too frightened by the fighting to leave the basement.

Dressed in red pajamas, Berdjohi Ananian, crippled at 52 with severe rheumatism, sat half propped up in her bed, a small Japanese radio next to her pillow and a cheap color Nativity scene pinned to the now-paneless window.

She had lain there unattended for days on end during the worst of the fighting, unable to move and left behind by the staff.

Her bright black eyes darting, she said in excellent French, "Of course I was scared." And had she been hungry? "I was so frightened I did not want to eat," she said.

And what had she done during that terrible time?

"I listened to the news on the radio," she said.