Sec. 1. This article applies to the sentencing procedure in a capital case for an offense that is committed before September 1, 1991, whether the sentencing procedure is part of the original trial of the offense, an award of a new trial for both the guilt or innocence stage and the punishment stage of the trial, or an award of a new trial only for the punishment stage of the trial. For the purposes of this section, an offense is committed before September 1, 1991, if every element of the offense occurs before that date.