Do effects that modify stats 'this turn' (like Grand Stratagem) apply only to units present when the effect resolves, or do they also affect units that enter the board later that turn?

Ruling: Effects that modify stats "this turn" only affect units that are on the board when the effect resolves. Units that enter the board after resolution are not affected.

Sequence:

• The effect resolves and applies to all units currently on the board
• Units summoned after resolution do not receive the modification
• Exception: Units that enter the board before resolution (such as by reacting to a trigger) are affected

Nuances:

• This is generally true for all cards without a permanent (continuous) ability
• If a card works differently, it would have very specific wording, such as: "All friendly units gain +5 might this turn and for the rest of this turn, when you summon a unit it gains +5 might until the end of this turn"
• Imperial Decree is mentioned as an exception to this general rule