You enlist in the army and enrol at school.

Dictionary definitions define "enlist" as enrolling in the army. Dictionaries are often not worth the effort. I can also enlist the help of someone but I cannot enroll them as I have no list of mentors. I believe that #GuideDogSaint lost an "l" in his post. I wish I could enlist the aid of italki to allow us to edit/amend our posts.