SPRINKLE gelatine over lemonade concentrate in microwavable bowl; let stand 1 minute. Stir. Microwave on HIGH 45 seconds. Stir until gelatine is completely dissolved.
PLACE blueberries and sugar in blender container. Add gelatine mixture; cover. Blend until pureed. Add ice cubes; cover. Blend on high speed until smooth and frosty.
SERVE immediately for a soft slush or cover and freeze at least 4 hours for a firmer sorbet.