Treefrog mentions the "brava!"s emanating from Gerald Arpino's box at a performance of the Joffrey Giselle. It reminded me of the time I saw and heard Mr. Arpino at City Center, leading the applause for his company. He could scarecely contain himself -- a one-man standing-cheering-bouncing ovation. It impressed me a lot, since I couldn't help contrasting it with an audience reaction I was more familiar with -- that of Lincoln Kirstein at NYCB. Actually, Lincoln's was more of a non-reaction -- h