If a person was divorced as a believer, it would permanently disqualify him from being an elder since it shows that he does not fulfill the requirements of an elder as listed in I Timothy 3 and Titus 1.
Certainly, his repentance will bring about forgiveness and restoration of fellowship with God, but it also shows he did not rule his own house well. It is this element that would disqualify him from serving as an elder. However, he could certainly have ministries in other capacities, but not in a ruling position of a local church.