Combine lemon juice, sugar, lemon rind
and 1/2 cup of water in a medium saucepan over moderate heat. Stir until sugar is dissolved, remove
from heat. Stir in the rest of the water and
lemonade and pour mixture into a baking pan, cover and freeze for 4
hours. Break up ice crystals and return
mixture to the freezer. Freeze until set. If using an ice-cream machine, process
according to manufacturer's instructions. Blend or process raspberries with the
jam and liqueur until smooth. Push mixture through a sieve, discard
seeds and server sauce with sorbet.