General in Reserve

[umbratica]

Can I set up my general (Lord-Arcanum therefore enabling Sequitors-Battleline) in reserve, set up my Sequitors (counting as battle line) on the battlefield, and if so is there just no general on the battlefield until the Lord-Arcanum arrives or is another hero general, and if so does the army list's general, the Lord-Arcanum, become general upon arrival? And if there was no hero set up before the battle begins, does the first hero arriving become general?

[Landohammer]

The only restrictions are that your General must be a Leader and cannot be an Ally.  In matched play you do not pick a new general if he dies (GHB pg 55 paragraph 4)

So you can totally set up your Lord Arcanum in reserve and it would not impact his generalship in anyway. 

Picking successor Generals is in the basic rules but its meant for Open play. The GHB specifically removes it for matched play.