What has big stars, lesbians, and accusations of censorship? No, it's not a Howard Stern special-it's just the latest skirmish between ABC and Roseanne and Tom Arnold. The ruckus began when Tom, the series' executive producer, accused the network of rejecting an episode in which Roseanne and guest star Mariel Hemingway kiss in a gay bar. The network refused to comment on the show, scheduled to air March 1, and both the Arnolds declined requests for interviews, though their spokeswoman says, ''(The network has) said to Tom they will not air the episode.'' Could this just be another publicity ploy to leverage Roseanne's ongoing contract negotiations or to create hype for Mr. Arnold's new CBS show, Tom? ''The Arnolds like to make the headlines first,'' says a New York-based media executive. ''They like to force the issue.'' The decision to pull the plug on the lesbian kiss seems somewhat out of synch with ABC's liberal policies (its NYPD Blue regularly features nudity). & Moreover, the ruling doesn't appear to be a result of protests by advertisers or affiliates. ''Had the network decided to run it, we would have had no objection,'' says Joe Franzgrote, of the ABC affiliate in Denver. The media exec takes issue with Arnold's claim that ABC was afraid the kiss would lose the network $1 million in advertising. Although companies are always cautious when it comes to gay issues, she says, ''When you buy Roseanne, you know you're going to get something that pushes the envelope. The show already has gay characters.'' Banned or not, the kiss might still show up on ABC. A crew from 20/20 was filming a profile of the actress the day the episode was shot. While the 20/20 story is still being edited, it's slated to run Feb. 18.