Mix together lemon juice, remaining 1 cup water and 3/4 simple syrup. Place a clean, raw egg in a 2 1/2 cup measuring cup and pour lemon juice mixture over the egg. If it floats and you see about a quarter sized piece of shell floating on top, you have the correct amount of sugar. If it is not floating enough, add more simple syrup, or if it is floating too much add more water. Having the correct sugar content will allow the sorbet to freeze properly and not be too hard or icy.