[PvK]

In my limited experience, Black Templars (or other Knights) are great as a flanking force that arrives just after the main body of HI and/or cannon fodder have met their melee. The have devastating attack but aren't invulnerable by any means, so its best if they aren't charging straight into combat by themselves. Best if the enemy is mainly committed to fighting something tougher and/or less expensive when your cavalry hits their flank or rear.

I haven't had to deal with Ithilids yet, but if they are doing mental attacks, then expensive armor should stay away from them. I have a similar issue fighting Jotunheim with Ulm, because Jotun giants can squash Ulm guys with giant weapons and boulders. In both cases, I'd only engage with plenty of cannon fodder, such as whatever cheap units you can get (militia, barbarian knife fodder, mercenaries, provincial defense) and mobs of archers and/or magical tricks (though sending expensive mages could be a bad investment unless they have a good plan and good protection).

Anyway, that'd be my semi-novice advice.

PvK