Arm/face contact
 

Recent situation: late in game (already decided game) A1 has control of a rebound, and is slightly off balance. B1 guarding aggressively - all over A1. As A1 straightens and turns, back of A1's arm catches B1 in the face and knocks her to the ground. I know this contact was discussed back in 2012 as a point of emphasis, but I'm still unclear (and reluctant to assert) that this contact was an "intentional foul" by the offensive player.
Any guidance?

It could be everything from incidental, to intentional to Flagrant or just a common foul. And it could be a foul on the defender if they were in the vertical space of the offensive player.

This is really a HTBT situation and not easy to say reading words on a screen. But you have options. There is no automatic anything in this case.

Peace

Elbow To The Head ...
 

I assume that by "turns" you mean pivoting, and in this case it appears that A1 is not swinging elbows excessively.

Pivoting (elbows moving with torso) is a legal move, but when the opponent gets hit in the head (mouth) we have to rule an intentional foul.

An opponent getting hit in the head by a player excessively swinging elbows (not this situation) could lead to a ruling of an intentional foul, or a flagrant foul.

If A1's elbow was stationary (no pivot), contact to the head with a stationary elbow may be incidental, or a common foul (like extending elbows on a screen).

The NFHS want us to deal with contact to the head harsher than contact to the body.

NFHS 2012-13 Points Of Emphasis

Contact above the shoulders. With a continued emphasis on reducing concussions and decreasing excessive contact situations the committee determined that more guidance is needed for penalizing contact above the shoulders.

A player shall not swing his/her arm(s) or elbow(s) even without contacting an opponent. Excessive swinging of the elbows occurs when arms and elbows are swung about while using the shoulders as pivots, and the speed of the extended arms and elbows is in excess of the rest of the body as it rotates on the hips or on the pivot foot. Currently it is a violation in Rule 9 Section 13 Article.

Examples of illegal contact above the shoulders and resulting penalties.
1. Contact with a stationary elbow may be incidental or a common foul.
2. An elbow in movement but not excessive should be an intentional foul.
3. A moving elbow that is excessive can be either an intentional foul or flagrant personal foul.