Missed "Barchu"

Hi,

Normally, one who is called up for an aliyah to the Torah calls the congregation to bless G-d, saying "Barchu et HaShem hamevorach," and then, after the congregation responds, he continues with the berachah for the aliyah (asher bachar banu). If he forgets to begin with Barchu, then once he says HaShem's Name in the berachah for the aliyah, he does not go back to say Barchu.

(Rivivot Ephraim 1:101)

Have a great day,
Mordechai