Feasibllity of running a do/while/break loop in Setup?

I wish to run this once in Setup where the LCD prints "Press Button when Ready" and it loops on the switch changing state before proceeding.

Is this possible? Kindly advise how to execute as I have tried many variations that result in the code never responding to the switch press or ignoring the switch press and running the rest of the program.

BTW the rest of the Loop performs correctly - measuring a pressure sensor with a MCP3421 and UNO.

Sounds like you want the end of your setup() to be:

      LCD.print(F("Press Button when Ready"));

      //  Wait for button press
     while (digitalRead(buttonPin) != LOW);

     // Go on to loop()
}

Of course you left a lot out of your description so I had to make some guesses.

Kindly advise how to execute as I have tried many variations that result in the code never responding to the switch press or ignoring the switch press and running the rest of the program.

Yes, but the idea is to post your attempt(s) not just to say that some un-posted code doesn't work.

Many thanks JW... you helped solve my problem!!