EWTN Catholic Q&A
Non cardinal being elected pope
Question from Benny on 04-19-2005:

Has Canon Law been revised so that a non-Cardinal may no longer be elected Pope? Is it still possible although unlikely that a simple priest be elected pope? I know this has happened several times in Church history but not in modern times.

Answer by Colin B. Donovan, STL on 04-26-2005:

Yes, a simple priest can be elected. The Conclave Ritual has provisions for the Substitute of the Secretariat of State to contact the electee if he is not in the Conclave.