This surprises me...we do this at our Latin Mass and I never remember not doing it. Is it a new innovation?
See my #28.
The general rule in the TLM is to mimic the priest's signs of the cross during the spoken/audible parts of the Mass.
That would include the Gospel, but not when he makes the Sign of the Crosses during the Canon, for example.
In the Novus Ordo, the same applies, except you can't use the audible rule.
I don't know where this sprang up - my childhood parish in Minnesota had an "old-school" priest who essentially just turned around and began speaking English after V-II. Other than that, we continued on as before.
Then, suddenly, when I was about 14 (early 80s), we began to have people doing this.
I still do not.
I do not hold hands during the "Our Father."
I remain kneeling until rising for Communion (and most in my parish do not).