I have a quite dramatic solution to this: warm up onstage until some 15 minutes before the concert. Don't play scales, but a a little from pieces that you will not play during the recital. I have done this, and the presenter gets quasi-mad, yes. But I told them if you don't have a piano backstage this is what I will have to do, basta.
And then, to my huge surprise, it had two side effects: one, the audience likes it, and they actually get "warmed up" too, much more ready to listen from the very first note of the recital. Two, it really cut down nervousness considerably.
I listened to some CDs of live performances by Ignaz Friedman at Carnegie Hall. Before every piece he does some arpeggios in the key of the piece. Interesting.