I've seen on this site, a few times, words like benché, finché, fintantoché, etc. and while all of these are words that I know -- they seem to be contractions of a word and -che.
A few examples:
benché = bene + che finché = fino + che fintantoché = fintanto + che perché = per + che talché = tal + che tantoché = tanto + che
Is there a pattern or formula I can follow for creating new words like this? It doesn't seem like Treccani or other sources I use talk about this topic specifically.
It seems like, in that list, some of the words are adjectives, some are prepositions -- is there a particular rule on which are allowed and which aren't? For example, I can't do
con + che = conché can I?