This card's [When Digivolving] effect reads "You may place 1 card with [Royal Knight] in its traits and a play cost of 13 or less from your hand or trash under this Digimon as its bottom digivolution card. Activate 1 of that card's [When Digivolving] effects as an effect of this Digimon." At what timing does that [When Digivolving] effect activate?

This card's [When Digivolving] effect placed a [BT10-016 Jesmon (X Antibody)] as a digivolution card, then that card's [When Digivolving] effect played a [BT6-082 Sistermon Blanc], then I activated <Blitz> in this card's [When Digivolving] effect to attack. When does [BT6-082 Sistermon Blanc]'s [On Play] effect activate?

This card's [When Digivolving] effect placed a [BT10-016 Jesmon (X Antibody)] as a digivolution card, then that card's [When Digivolving] effect played a [BT6-082 Sistermon Blanc], then I activated <Blitz> in this card's [When Digivolving] effect to attack, and when the [When Attacking] effect deleted one of my opponent's Digimon, my [BT6-082 Sistermon Blanc] was deleted by the [On Deletion] effect of the opponent's Digimon.[BT6-082 Sistermon Blanc]'s [On Play] effect hasn't activated yet, so does it activate?