What should/can I say to a student I suspect has committed an academic honor code violation?
Answer: There are many variables in answering this question: the student and your relationship with him/her, the assignment, the timing, etc.
The Faculty Handbook instructs faculty to report suspected cases of honor code violation to the Assistant Vice President for Academic Affairs, and not to begin discussions with the student. You can explain to the student that when the time is right you will be willing to talk to him/her about the incident and any consequences, should they be called for.
Elon's honor code policy is designed to provide a fair and impartial inquiry into the circumstances surrounding a suspected violation. The goal of the policy is to protect the student by giving him/her a chance to explain events and to protect the relationship of the faculty member and student by taking away a possibly combative confrontation. The purpose of the honor code is not to isolate the student and the faculty member, but to allow an examination of the perceived problem that will help mediate their interaction.