Peel the apples and slice into thin equal slices.
Place the apples in a pot with lemon juice, lemon zest, water and sugar.
Bring to boil, then reduce heat and simmer for 10 to 15 minutes or until the apples are soft, stirring a few times.
Remove from heat and pass the apples through a fine sieve to remove lumps.
Stir in the Calvados and the sorbet base is ready.
You can either use an ice cream machine or just seal the mixture in a plastic container and place in the freezer.
Remove from freezer after 1.5 to 3 hours and stir contents.
This will allow the mixture to freeze more equally and achieve a smooth sorbet-like consistency. Freeze for at least 6 more hours (overnight is best) and serve.