ERRATA notes:

Yoke
for Size 5
The number of stitches at the yoke has been miscalculated from the row 1. It should read as follows:
Row 1: at the end 59 {63, 67, 71} sts
Please adjust all the following numbers accordingly adding one stitch.

Sleeves
for all sizes
Join MC and knit, increasing 4 sts evenly spaced across: 50{50, 54, 54} sts.
Next Row: Purl across.

Start Lace stitch pattern:
Row 1: K1, {K2, yo, ssk}, K1
Row 2: P1, {P2, yo, P2tog}, P1

It’s important to folow these numbers exactly as written to make a nice seam afterwards.