After half a skein of the Lorna’s Lace, I switched to the Whisper Solid, using two strands at once. I knit it up in garter stitch. After I felt it was big and fluffy cloud enough, I cast off several stitches in the center of the row (10-14?) and on the next row, I cast stitches back on using the backwards loop. After a few rows more, I started casting off 4 stitches at the start of each row.

And - TADA! Pretty cloud with a hole in it.