ENCOURAGING as it is to see live music flourishing in Hongkong, it's hard not to wonder about a forthcoming show at the Ko Shan Theatre. Come July 24, the To Kwa Wan venue will be rocking to the grounds of saucily titled band Lazy Mother something as part of a Hongkong Heavy Metal Association-organised gig. But these sounds may not be your run-of-the-mill heavy metal. According to the publicity material, the band will be performing everything from Led Zeppelin to The Beatles, to Bauhaus. Yes, Bauhaus. One suspects Peter Murphy might raise an ironic eyebrow at the prospect of being labelled HM. Call 734-9009 for details. WITH all due respect to Kamal and John Moorhead, the enthusiastic hosts of STAR Plus' In the Picture entertainment show, they have tomake way tonight for a real TV celebrity: David Frost. Frost will be getting stuck into pop star and walking hair complex, Elton John, in front of the cameras. This is an almost irresistible prospect, perhaps more so than John and Kamal ''reporting'' on the as-yet-unreleased films Jurassic Park and Last Action Hero. The show starts at 7.30 pm. BE ON the look-out for two movies which promise to perform brilliantly at the box office later this year. Both The Firm, starring Tom Cruise, and the Tom Hanks-Meg Ryan romance Sleepless in Seattle, are doing raging business in the US. Their success prompted humourist Jay Leno to comment: ''Two of the big movies this year are Sleepless in Seattle, about a man and a woman, and The Firm, which is about lawyers and money. So they're both love stories.''