If by conditioning you intend to smooth the beer out, precipitating yeast, tannins, etc. cold will be far more effective. Make sure the yeast has completely finished before crashing it. Really, the same goes for all beers, like Jim suggests. Ale or lager, cleanup by yeast is done warm, physical stabilization cold. British brewers have long since taken to a couple weeks lagering in beers that once were aged a long time.