  Let (K,v) be a valued field, Y a K-variety, G an algebraic group over K (not
necessarily smooth), and f: X->Y a G-torsor over Y. We consider the induced map
X(K)-->Y(K), which is continuous for the topologies deduced from the valuation.
Let I denote the image of this map.
  We prove that if (K,v) is henselian and its completion is a separable
extension, then:
  - I is locally closed in Y(K);
  - the induced surjection X(K)-->I is a principal bundle with group G(K) (also
topologized by the valuation).
