Lidia and Andrzej Orlowski, who arrived in this country as refugees from Poland six months ago with two children, three suitcases and nothing else, yesterday threw a big Polish-style party in Hyattsville for the people who helped bring them to the United States.

They invited 256 members of a Hyattsville church who got them out of a refugee camp in West Germany, found an apartment, paid their bills, bought food, baby-sat for their two young children, served as interpreters, taught them to drive and helped in a hundred other ways.

"These are the best friends for me and my family," said Lidia Orlowski as she welcomed members of the congregation of the First Methodist Church of Hyattsville to the party in the church basement. "They gave us a start in the United States."

The Orlowskis were forced to flee Poland last year for political reasons.

Andrzej Orlowski was a Solidarity labor movement leader in Wroclaw, an industrial city in southern Poland, when he was imprisoned by Polish authorities early in 1984 for his union activities. That May, Orlowski was given the choice of deportation from his homeland or continued imprisonment. He chose deportation and was sent to a refugee camp in West Germany.

Orlowski's family was allowed to join him six months later. Orlowski recalled yesterday how his daughter Monika, now 4, yelled and pounded on the window from inside the arriving train when she caught sight of him standing on the platform. His son Marcin, now almost 2, did not recognize him, he said.

Yesterday, Marcin and Monika tumbled and slid with children of church members across the wood floor of the church's Fellowship Hall, communicating in an international language of shrieks and laughter.

Earlier, during services, an emotional Andrzej Orlowski told the congregation of the 1,900-member church what their sponsorship and support for the past six months has meant to his family. In addition to financial help, he said, "We also had something more important -- warm feelings, good will and moral support."

The family is Catholic and attends services at the Hyattsville church as well as mass elsewhere.

Orlowski, 30, a lighting engineer who worked for a television station in Poland, hopes to get a similar job here soon. He and Lidia Orlowski, 28, an economist, have studied English intensively for the past six months at the University of Maryland.

Alex Witkowski, a retired engineer who emigrated here from Poland 32 years ago, is one of several volunteer interpreters helping the Orlowskis learn English. He said yesterday that almost everything in their Hyattsville apartment is labeled in English with a slip of paper.

Still, said Orlowski, as he tried to relate his feelings about being in the United States, the English comes hard. "I like America," he said. "This is a very good floor. Floor? -- No, grass. Grass? -- No, soil."

Yesterday, congregation members dined on keobassa, a Polish stew that Lidia Orlowski and others had made, and brown bread. A few couples danced the polka to accordian music. Hanging on a wall above them was a huge Solidarity banner -- the same banner, according to church officials, that for months was posted on the International Brotherhood of Electrical Workers headquarters building across the street from the Soviet Embassy.

This is not the first time the church has sponsored refugees -- it is currently sponsoring an Ethiopian immigrant -- but church officials said it is the first time church members have brought an entire family to the United States. In addition to thousands of dollars for the Orlowskis provided by the church as a whole, 256 individuals gave time, money and goods such as furniture and a car to the family.

"It was something everybody could support in some way," said Pastor Jack Ewald.