The refrain in 42:5, 42:11 and 43:5 links these Psalms. But it’s not exactly the same in 42:5 – there is some progression.
Lots of face references here. The Psalmist wants to see God’s face (v 2) because it will lift up the Psalmist’s face (v 5, 11, 43:5). The phrase is literally “the salvation of my face”. Maybe this is part of 43:3 as well: “send out your light and truth” could be a reference to the light that emanates from God’s face. Remember Moses requesting to see God, but not being allowed to see His face. But even that glory makes Moses’ face shine… Your face is the salvation of my face.
Besides the three stanza structure, there’s also a midpoint on 42:8 where the name JHWH is used instead of Elohim, and where the hesed of the LORD is proclaimed. While perhaps not exactly a turning point in the Psalm, it is a strong statement of faith even in the midst of discouragement.
It’s also another play on our primary role as respondents to God (in the same way that the salvation of our faces is via God’s face looking upon us); in v 42:4 the Psalmist remembers singing but can no longer do it, then in v.8 God sings to him – through which he is enabled to sing in 43:4. The primary action is always God’s.