The last three instructions before we get to the rubrics and rituals for “Sending of the Catechumens for Election.”
108. The rite is celebrated in the parish church at a suitable time prior to the rite of election.
109. The rites takes place after the homily in a celebration of the word of God (see RCIA 89) or at Mass.
110. When the Rite of Sending Catechumens for Election is combined with the rite of sending for recognition by the bishop the (already baptized) adult candidates for the sacraments of confirmation and eucharist (or: for reception into the full communion of the Catholic Church), the alternate rite found on (RCIA 530-546) is used.
Most parishes find that suitable time to be the Saturday before election, or the weekend before Lent. My present parish does not send baptized candidates to the Rite of Election, so we never use the combined rite.