An implantable electrode arrangement for a cochlear implant system is described. The arrangement includes a flexible intracochlear electrode array having an outer surface with electrode contacts for applying cochlear stimulation signals to target neural tissue within the implanted cochlea. A flexible extracochlear electrode lead is coupled at a lead proximal end to an implanted signal processor that provides the cochlear stimulation signals, and connected at a lead distal end to a proximal end of the electrode array. A lead holder is connected to the lead distal end and has an initial shape. The lead holder is malleable and adapted to be intra-surgically deformed into and retain a new desired shape so as to secure the lead distal end at the electrode opening into the implanted cochlea and decouple post-surgical mechanical strain at the lead distal end from the electrode array.