I am dealing with this same issue. I believe the lower line with the hose clamp is the high pressure feed to the steering box. If you grab it and try to move it, it should actually be a rigid line. That hose clamp might be lose, or the fitting at the reservoir might be loose. You might also be leaking at the pulley. I suppose there's also the small chance that you're leaking at the return line (the line in the upper right part of your picture), or the seal where the pump mates with the reservoir. As you've discovered, it's hard to pinpoint it because there are so many possible places for a leak in such a small area. I'm no expert, but my guesses are a leaking high pressure fitting, or a leaking pulley (simply based on mechanical arguments). IDK if you can pour some UV dye in the reservoir and then shine a black light under your hood to help; I know they do that for AC leaks.
Also, I've seen replacement videos as I'm thinking of replacing this myself. The job doesn't look too hard - if you can change oil, do breaks, etc., you can replace the pump. However, it just kinda looks like a pain in the ass, because there's a bunch of stuff you have to move to get to it. And then you have to consider the "while I'm in here" jobs, esp the water pump. I don't know where you live, but I figure that tripling your parts cost is a decent estimate for a shop to to the p/s pump ($150 pump = $450 shop job).
