Using in situ small-angle X-ray scattering, the electric field induced orientation in a block copolymer having a cylindrical microdomain morphology was investigated. Studies were performed with the copolymer in different initial states. Beginning with a disordered copolymer, composition fluctuations are oriented by the electric field. Following cooling across the disorder-to-order-transition, microdomains are oriented parallel to the applied field. Beginning with a microphase-separated copolymer where the microdomains are oriented normal to the field, the domain orientation becomes unstable at high field strengths, and the microdomains reorient in a piecewise manner.