mac - ONE single clunk upon brake application may be your half shaft - you should fully lift front off ground and compare both R. AND L. shafts' rotational "Slop" w/vigorous CW & CCW twists BUT FIRST you eliminate problem's side for LOOSE Lugnuts (even Drvr's side too

) .Could be lower Ctrl. arm or Tension rod - they connect to frame and will give an initial "clunk" and you would give'em a "Hell-Shake" to see if they're loose/warn. Then again if any Caliper hdw. like brkt bolts or the smaller "Caliper bolts to brkt.".Yes pads and shims can just separate and simply be positioned WEIRD giving ONE knock .Balljoints (tie-rod and of course "Lower" ) be checked. Not limited to these and these many times clunk-upon brake and "declunk" again upon release of brake?
And the above things actually make more noises when turning ,releasing,accelerating ,I'm describing the "initial" clunk that gets your attention.
You know. Then a CONTINOUS Clunking would be a whole nother thing

Like the half-shaft might do something like that , cause if damaged and rotating it becomes a "train of noise('s) ".
These guesses are guesses because if you could carefully note like mentioned here , clunk = once,steady & repetitve, what action(s) ie. brake will cause AND diminish / change / curtail the clunk ? -etc. Turning in combinations with accelerating ??

So go & thoroughly test and take notes , then look at things I mentioned
and other more experienced members suggestions - you'll probly find SOMETHING !

If your luck is like mine it'll be a loose hood hinge

G 2/21/2018