It took a rainout in Detroit to keep the Baltimore Orioles atop the American League East tonight. Certainly, the Orioles did nothing here to affirm their No. 1 status, as the last-place Cleveland Indians completed a three-game sweep with a 4-3 victory. It was the Orioles' fifth straight loss.

Right-hander Lary Sorensen struck out a career-high nine batters in a route-going, six-hit performance. But it was the Indians' devil-may-care attitude on the bases--and the Orioles' slowness to react--that made the difference in this one.

Cleveland produced three fourth-inning runs by having a man score from first on a double to right, from second on an infield single following a stolen base and from third on a suicide squeeze. A stolen base contributed to the Indians' other run, beating Mike Boddicker, who had been 7-0 at home.

"The kid pitched a fine game, but he wasn't the same when we had men on bases," said Cleveland Manager Pat Corrales.

Baltimore's scoring came in one quick burst, a three-run homer into the right field seats by Ken Singleton in the fourth inning following a double by Dan Ford and a walk to John Lowenstein. That gave Singleton 13 homers and 54 runs batted in this year, with a career RBI total of 999 that left the Orioles one short, too.

While Corrales praised Sorensen he pinpointed the absence of Baltimore first baseman Eddie Murray, still nursing a sore knee, as the key to the sweep that gave Cleveland the season series, 7-6.

"They're a tough club, it's just that their main man is out and they know it,id. "You go out on the street and try to find somebody like Eddie Murray. You won't have any luck."

Actually, Corrales almost snight. Baltimore Manager Joe Altobelli said he had planned to insert Murray as a pinch hitter for struggling Tf Nolan had singled with one out. "When (Joe) Nolan doubled, I decided not to use him with first base open," Aey would pitch around him even with his bad knee. That's how good he is."

Aside from Singleton's homer and t, which left the Tigers tied with Milwaukee for second place, just one percentage point away, the Orioles had very little of a positive nature to discuss on th-game series opening Thursday night in Chicago.

Boos began to be heard before many of the 24,211 fans--18,29nter the park and search in vain for a scorecard. Third baseman Cruz charged a bouncer by Alan Bannister, the game's second batter, and was caught between hops, the ball skipping past him for what was officially and unpopularly recorded as a single. Bannister stole second, reached third on Pat Tabler's bloop single to right and scored on Andre Thornton's force-play grounder.

The Tribe danced the Orioles dizzy in the fourth. Gorman Thomas started things with a walk and came all the way around on Ron Hassey's hit-and-run single past first baseman Jim Dwyer, Murray's replacement. Actually, Thomas slowed after rounding third, then accelerated when rightcted to throw to second, where a potentially close play was erased when the ball bounced away from Dauer.

"nd I knew I could score," Thomas said. "We can't just sit back and wait for power. Power isn't our forte, shal up on Franco's infield out and scored on George Vukovich's suicide squeeze. It became 4-0 as Toby Harrah singlove, stole second and scored from there on Bannister's seeming routine grounder to shortstop. Cal Ripken let the ball bounce twice instead of charging it, and Bannister beat Ripken's throw. While Dwyer held the ball, Harrah kept on running and did not need to slide when Dwyer finally reacted.