By the way, don't just hand over the money. Pay as you go. It may cost more but your money is safer. Ignore inducements to pay lots up front. It's fair to keep you account in the positive by a reasonable amount but you shouldn't have to pay for the whole course in one go. Some schools have an account that protects student fees in the event of the FTO going out of business. Ask about this. So many people in the last few months have been caught out by FTOs going broke.
Have a look at the facilities. Are there briefing rooms where your flight can be analysed in private? What's the flight planning area like.
Better than asking questions, see if you can have a ride in their simulator. It might give you a feel for the instructors' style. Better still, see if you can take a back seat ride.
If you can chat to other students, they may give a good info. If you can get details of past students, they may could offer more of an insight. For example, how many stayed to do the IR?
What is the instructor/student ratio. How many aircraft. How many hours on the complex type (eg Piper Arrow)
Not a lot of point in asking about the weather. You've no way of knowing what it will be like except in the short term. You will need good weather for most of the CPL course - nav, handling, emergnecies.
Choosing a school is a difficult but import decision. You have to judge by your own criteria of course but I hope this helps!
AP