PLEASE HELP...i wanna know if i could ask for his last name or email?

I was working @ an office for about 2 months this summer. On the first day, i met my coworker mike (who's in his last year of law school)...he answered the door, welcomed me in & introduced himself & all the staff members to me. 2 out of 3 of the staff members are part-time adults & the third member is a full-time adult (who is always there everyday at our office). I met another guy (nick) at the office a month after i started working who just graduated college & told me that he was a full-time summer intern. The full-time woman, fran, observed me throughout my working experience & asked me if i would be interested in coming back to work at the end of the summer (now)...so now it's just me & fran on the staff...bec. both mike & nick went back to grad school, so i was filling in for them. Nick called the office & i heard fran talk to him...but when she came to talk to me she said nick was asking for me/how i was doing...i was sooo happy yet shocked that i guy i saw in person for a few days would really ask about me...i miss him but i don't know his last name to find him on facebook or don't have his email, so do YOU think it would be ok if i ask fran for it? if so, how could i ask her? thanks =)