You are correct, the Element shares its K24 engine with many other K series Honda/Acura cars. For a complete list of cars with K series engine check this out.
Check the master cylinder, there is a triangular plate, that can develop a leak. It can be replaced with a Civic master cylinder, that does not have the extra valve assembly inside and would be less prone to developing the leak.
4fc5faceddf9a89b81.jpgYour 03 Element. It's part number 7. Honda part number 46920-S7A-A03
The Civic master cylinder that I'm talking about is here
71b82b5ee5221a53038.jpg 05 Civic. Part number 6. Honda part number 46920-S5A-G04
It might be a pain to get to, since on the RSX it's high on the firewall and tucked into a corner.