I mean something like this:
I'd like to hide them like this during "downtime period" or "do not disturb mode". I'd like to hide them both on the lock screen on the status bar at the top of the screen.
I'm interested in something like this because I like not to be disturbed around bedtime, or when I wake up during the night and glance at the screen to check current time.
For example: today morning I woke up ahead of time, very much not refreshed, and when I went to check for time on my phone, I saw a notification which got me excited and unable to fall back asleep. It's situations like this that I'd like to avoid.
Source for the picture. I presume the notification-hiding functionality might not have made its way into Lollipop -- since I haven't seen it in settings. Or has it?