By Elizabeth Pineau and Lucien Libert ARRAS, France (Reuters) -French President Emmanuel Macron has maintained and possibly slightly extended his lead over far-right challenger Marine Le Pen following a prickly television head-to-head debate which he was judged to have won, polls showed on Thursday. With just three days to go before Sunday’s election run-off, the two were back on the campaign trail – Macron in a Paris suburb with a strong left-wing vote, and Le Pen in the north of the country where she has a loyal following. “Why wait for Macron to step down when, by using your vote, you can f…