When does a lycanthrope change?

[0-hr]

Tonight, a player, who had been acursed with lycanthropy (wolf) was struck by an ogre and took enough damage to force an involuntary change. My question: when does the change take place? We rolled the check immeadiately and ruled that that change would take place on the characters next turn (taking a standard action to complete). Unfortunately, the other bad guys finished off the character before his turn ever came around.

Had he changed immeadiately he would have been fine, so I wanted to check the rules and see if there was a clarification anywhere on when exactly the change should take place.

Here are some random quotes from the SRD:

Alternate Form (Su): All lycanthropes can shift into animal
form as though using the polymorph self spell (though their gear
does not change). Wererats, weretigers, and werewolves also can
assume a bipedal hybrid form with prehensile hands and
animalistic features. Changing to or from animal or hybrid form
is a standard action. Upon assuming either form, the lycanthrope
regains hit points as if having rested for a day. A slain
lycanthrope reverts to its humanoid form, although it remains
dead. Separated body parts retains their animal form, however.
This shapeshifting ability can be difficult to control (see
Lycanthropy as an Affliction, below)

...

The afflicted character must make a check at moonrise
each night of the full moon to resist involuntarily assuming
animal form. An injured character must also check for an
involuntary change after accumulating enough damage to reduce his
or her hit points by one-quarter and again after each additional

...

Thereafter, the character is subject to involuntary
transformation under the full moon and whenever damaged in
combat. He or she feels an overwhelming rage building up and must
succeed at a Control Shape check to resist changing into animal
form (see the sidebar).
one-quarter lost (save DC same as for full moon).

 

[AuraSeer]

I always assumed that the damage forces him to spend his next action shifting. It doesn't seem logical that he'd shift instantly and get a "free" standard action between turns.

If it were faster to shift involuntarily, that could be an advantage sometimes. A lycanthrope in human form could use one of his iterative attacks to hit himself, doing enough damage to trigger the change, and get the benefit of a Full Attack and a shapeshift all in the same round.