It does not occur to you—or at least it did not occur to me—until the final sequence of this remarkable movie that Sciamma has not taken the usual pains to orient us in historical time. We get none of the usual period-pic hints meant to situate us snugly within a particular context: No obligatory references to kings or wars, no obvious recent inventions, no title card at the beginning of the film to let us know that it is 1728…