Sorbets are so easy to make. By adding a little bit of alcohol, it helps to prevent the sorbet from crystallizing. You don't need an ice cream maker, and can simply freeze this and scrape it with a fork. But, an ice cream maker does make this a lot less work to do.
Adapted from foodiewife-kitchen.blogspot.com
Wash and dry lemons. Using a microplane grater, remove the zest from two to three lemons until you have about 2 tablespoons of lemon zest. Place water, zest and sugar into small saucepan and bring to a boil. Let boil for one minute and then remove from heat. Juice the lemons until you have 2 cups of juice. Pour juice through a chinois or sieve to remove seeds and pulp. Add 1/3 cup of limoncello to the juice and place in an ice bath to chill. Pour cooled zest and sugar mixture through chinois or sieve into ice bath with juice. Stir to mix and chill mixture in ice bath until less than 45° F. NOTE: I simply chilled this mixture in the fridge for a couple of hours. Pour into ice cream maker and freeze according to your maker's instructions. Once chilled, remove from ice cream maker and place in dedicated (odor-free) container to let ripen in the freezer for several hours. Because of the alcohol, it will always be a tiny bit soft.