The line you ask about from Shakespeare's Sonnet 18, the "Shall I compare thee to a summer's day?" sonnet, is:

When in eternal lines to time thou grow'st.

I assume you're wondering about the transversal Shakespeare employs.  He takes the verb, grow'st, out of its natural place in the clause and places it at the end.  This is a common practice in poetry of Shakespeare's day, and is usually done to create a rhyme.  In this poem, "grow'st" is used to rhyme with "ow'st" from line ten. 

The grammatically correct word order would create this line:

• When thou grow'st in eternal lines to time.

I assume that's the word order you're looking for.

Transversal is frowned upon by poets today due to its artificiality, but its use was common in Shakespeare's time.