The horizontal line for the 3 asterisks is an old EBAE format that is no longer valid because EBAE formatting is no longer used. I can't find any specific mention of it in the new guidelines. And here is why they are called guidelines. I would suggest the following.
First, blank line usage for the change of context is the same. If the change of context is at line 24 or line 25, the material resumes on line 2 of the next braille page, or line 3 if there is a running head. If the change of context falls in the middle of the braille page, you have a blank line where it occurs.
I think you could populate the blank line with the three centered asterisks, because that is essentially what the print does. I don't think you would need additional blank lines before and after the asterisks.