As I understand it, 'for' is a coordinating conjunction. Learning German as a second language has taught me specifics about reforming sentences, but it is an awful lot less common in English. If I were to rearrange the sentence: "I ate lunch, for I was hungry," so that 'for' was the first word of the sentence, by my reckoning I should end up with "For that I was hungry, I ate lunch." Does this new sentence have any grammatical errors? I inserted the word 'that' after 'for', because without it the sentence didn't sound right. Should I have? Is there a rule for that? Thank you in advance, an aspiring author.
Additional Information: I am not having problems with the sentence, this is a general question to increase my knowledge of the manipulations of coordinating conjuntions.