WHAT a flustered lady was Elisabeth Cassegrain-Thomas when we bumped into her in Pacific Place yesterday. Frenchipoo Elisabeth - a staple on the invitation lists of most society events - was waving her arms about animatedly trying to explain that she was having a ''French Week'', meaning: she had so much to do. We listened intently as she reeled off a litany of pressing assignments. ''I've got my father arriving from Paris, my daughter's first confirmation coming up, my birthday party to organise and I've had to arrange for nearly US$18 million worth of jewellery to be picked up from Kai Tak airport.'' Thinking perhaps that this was an early birthday present (she volunteered the information that she was 39!) from an admirer we pressed for more details. But it was all too innocent. The jewellery and other objets d' art were being sent over here by Garrard, the jewellers to British royalty for yonks (their duties include the regular maintenance of the Crown Jewels), which is staging an exhibition of its silver finery at its boutiquein Pacific Place from today until next Tuesday - an event launched last night with a cocktail party. On the professional side, Elisabeth has much cause for celebration, too. She has been appointed as Hongkong manager for Garrard, and also as Far East representative for Asprey. We can see the new workload making inroads into lovely Elisabeth's hectic social life. Perhaps that explains the fluster!