In a medium saucepan, combine the water, sugar, and lemon juice. Bring to boil. Cool in a mixing bowl. Freeze in an ice cream maker. When almost set, spoon in the meringue, (see recipe below) and 3 ounces of Champagne, and continue churning in the ice cream maker until creamy and set.
Boil water and sugar to a temperature of 230 F to 240 F.
Beat egg whites in an electric mixing bowl until medium firm. Slowly, add the hot sugar while continuing to beat the whites, and beat until cool.
Serve in chilled champagne glasses. Pour remaining Champagne over sorbet.