In my Talk To Me In Korean book 'Real Life Conversations For Beginners', there is a dialog which includes the translation: "Are you a student?" / 학생 이세요
I was expecting the sentence to be 학생 이시에요, if the honorific suffix (으)시 is to be used. Why did 시에 become 세? I suspect this is a contraction, yes? Are there general rules for these type of contractions for pre-final endings?