There are a number of aspects to this.
If the work is hourly and is not being delivered to you as a productized thing, then you should probably supply the environment for development.
This is even in light of the "tools of the trade" argument. I view it more as staff augmentation, and you are essentially the employer of the moment.
One big factor to consider is version control and control of the source code. If you don't own the environment that the developer works within, then versioning is anybody's guess.
Another factor - slowly disappearing with open source stacks - is the cost of the tools. A few years ago, Delphi Enterprise Edition was priced at around $3000. No way I'd buy it out of my own pocket for an hourly assignment at commodity rates. So be realistic about what burden you expect the freelancer to take on.