Q:

How to ask "when do you open" and "when do you close"?

In a shop or any other public place I can ask "¿Cuál es tu horario?" to mean what are the working hours, right?
But I want to ask precisely when they open and when close.
What'll be the proper way to ask this?
And what form of a verb will I use?

"Tu/Usted?"

Or

"They"?
"Se + verb"?

A:

If I'm not wrong you can use:

"¿A qué hora abre?"

to ask for when they open.
And to ask for when they close,  

"¿A qué hora cierra".

I'm from Argentina and we use this form to ask these questions!

