Soften gelatin by sprinkling over milk in small bowl. Combine water, grated zest from 1/2 the lemon and sugar in measuring cup and microwave on high for 60 seconds until sugar dissolved. Cool slightly then add to softened gelatin. Puree canteloupe, juice of lemon and cassis. Add a little milk mixture, if necessary, to puree more easily. Combine all ingredients and chill thoroughly. Freeze in ice cream machine according to directions.