We have devised a novel route towards a nanoscopically striped surface pattern with long range order via the self-assembly of an ABC triblock terpolymer thin film exposed to an in-plane electric field. Via the interplay between surface interactions and the effect of the electric field the lamellae were oriented both perpendicular to the plane of the film and parallel to the electric field. Moreover, quasi in-situ scanning force microscopy measurements were used to follow the reorientation process as a function of time and to yield insight into the microscopic steps eventually leading to the ordered microdomain structure.