¿ Missing in Strings

I have noticed that the following strings are sometimes missing the inverse ¿ at the beginning of the question which is grammatically incorrect in Spanish.

Can be made ahead? ¿Se puede hacer por adelantado?
Can be frozen? ¿Se puede congelar?
Good for leftovers ¿Se puede guardar para otro dia?

I think that the recipes that were created prior to my involvement with the project are the ones missing the ¿ mark. I don't know if there is an easy way to correct this that would not be too time consuming?