Split Upper / Lower case + concatenate rows

[p45cal]

The arrays are only 2 cells wide. You select the two cells, adjust the formula, then ctrl+shift+Enter to enter the formula into both cells. Then you can copy the pair of cells down.

[Biespet]

thanks p45cal

@snb, my appologies, I thought it didn't make a difference.
apperently seen the other solution, it doesn't.