Just say, This is (your name). I spoke with you last week (or whatever) and you suggested I apply online for the job we discussed, then call you. I ve applied online and was following up to see what the status of my application is. Practice that until you can feel comfortable saying it, then call.
When you call back, ask for him by name, give your name and tell him that you had spoken to him about applying for a job on line, you have done this, and you were wondering if you were being considered for this job. If he says that he hasn t made any decision thank him for his time and ask him if you can call him back in several days. Good luck, I hope you get the job.