Since there is no instruction in the General Instruction of the Roman Missal (GIRM) with respect to the deacons using the Orans posture at any point in the Mass, the deacon should not use it, and the lay faithful should follow his lead and example. (…) The priest and deacon should never instruct the lay faithful to use the Orans posture during the Mass.
Read full instruction by the Archdiocese of Portland here.