I BET Alice Patten's classmates groaned wearily when she told them yesterday she was dashing off home to have lunch with Elton John. When it comes to classroom one-upping that must take some beating. The Rocket Man was at Government House with his manager John Reid to join Chris, Lavender and Alice (left) for a ''Chinglish'' meal of seafood, fried vegetables and rice. According to my deep penetration agent at GH (I really must remember to send him his cheque), it was a pretty convivial affair, the conversation ranging from the Australian elections to the latest British Budget and (surprise, surprise) the fortunes of Watford Football Club. Elton, sensitive soul that he is, didn't bring up the rather distressing subject of Hongkong post 1997, and the Governor, quite sensibly let it rest, too. If it is any consolation to 13-year-old Alice's classmates, Mum packed her off early without so much as a photograph with Elton so she could get back to school pronto.