What could that noise be? (Escort)

My (somewhat limited) car knowledge is puzzled. There is a scraping/creaking noise coming from the left front side of the old Escort under braking. The first time I heard the noise I thought it was an indication that the car really needed a brake job.

But I did the brakes (new pads/rotors/fresh calipers) and the noise is still there and has been getting louder. Loud enough that it's slightly alarming over all the usual rattles that old tin box makes so it's significant.

So... Since the it's coming from the wheel hub area I thought it might be a wheel bearing or cv/axle noise. But... It only ever happens under medium braking as the car is rolling to a stop. If I let off the brakes the noise stops. Not under acceleration or turning. Not in reverse. It sounds like it's one noise per wheel rotation.

A couple days ago I jacked it up and took the wheel off to take a look. Nothing seemed broken and the wheel spins freely with no noises.

Also if I push down on that corner of the car it makes a noise similar to the noise under braking. But that could be old struts/springs and unrelated.

I'm going to take another look-see tonight or tomorrow. What should I be looking for that I haven't thought of yet?

Is there a rock stuck in there somewhere?

In reply to EvanB:

Ha. Not unlikely considering the amount of dirt roads it sees but I think I'd have seen that between doing the brakes and other stuff. I've probably had the car up and down and wheels on and off at least 5 times in the past two weeks.