In fact, totally clear for me too.
You can’t fly the circuit if the reason for going missed is that you lost visual contact with the runway 
You can’t fly the circuit if the reason for going missed is that you lost visual contact with the runway
Believe me, I can fly a near-perfect circuit on instruments alone. Would not be the first time…
If the GA is instructed by ATC they most probably will add some clearance like “join LH/RH circuit, middle of downwind,…” . If the GA was your call then start with a climb straight ahead to MSA. Given the speeds we fly ATC will come up with something more convenient in due time.
Given the speeds we fly
Define “we” … GA has a lot more to offer than a Pa28 and a C172
OK, a little less time when you’re jethoppin’ but the same principle applies :-)
I can fly a near-perfect circuit on instruments alone. Would not be the first time…
I am sure you can but what does it give you?
It doesn’t establish you on the IAP because you are too close in, and turning left base and descending onto final, in IMC, is dodgy. I believe that’s what N403HP (based where I am) was doing at LOAV, having cancelled IFR a long way back and flying a circuit (in totally solid IMC, for sure) for the benefit of Vienna radar which was just up the road. It this could be done reliably then there would be no need for IAPs
If one loses visual contact when e.g. breaking to the right in a circling approach, then a left turn to end up over the runway and climbing (as if going around from an IAP to the other end of the runway) is the right thing to do.
I am sure you can but what does it give you?
I am thinking about the little airfield where I do my 5NM visual approach instead of the 25NM RNAV/GPS procedure and right on final a rain shower or a patch of fog briefly brings the runway out of sight and forces me to go-around. The three minutes required for flying a traffic pattern might be enough for rain and fog to move far enough away for a second approach. Of course I would not do this in Innsbruck or Sion.
You can’t fly the circuit if the reason for going missed is that you lost visual contact with the runway
Well no, but I tend not to accept visual approaches in circumstances where that is likely.
Of course I would not do this in Innsbruck or Sion.
Or Shoreham EGKA, at 800ft which is the lowest allowed circling N of the airport
This is the view from the 02 end:
