"The enemy card Dol Guldur Orcs provides an example
of a shadow effect that triggers whenever the card is
dealt to an attacking enemy as a shadow card." (pg.23 of the LotR LCG Rulebook)
The shadow effect will be played immediately instead of being played face down. at the time that the card specifies: "after Dol Guldur Beastmaster attacks." which from my understanding is after the first stage of the combat step.
"1. Choose an enemy. The first player chooses which
attack (among the enemies to which he is engaged) to
resolve first." (pg.18 of the LotR LCG Rulebook)
I say this simply because on page 16 it states about the engagement phase
"Note that during this phase enemies do not attack
players, they merely engage players. Enemies attack
the players with whom they are engaged during the
combat phase (see page 18)."(pg.16 of the LotR LCG Rulebook)
but of course there is still confusion on the definition of after. I say it is after all 4 steps have taken place... because that is literally after he attacks. The Shadow effect would resolve and if it says +1 force... tough noogies. but that's me after some examination of the rule book and the card text. maybe not designers intent. It's tough getting all this jazz to mind meld.
please counter act me if you have some good points on the contrary.