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He collapsed on his back, following which he tried to get up.

Is it okay to use 'upon which,' 'after which,' and 'following which' in these cases? What are the other options (except during which)?
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Again, these all are too stilted and awkward to live.

He collapsed on his back, and then he tried to get up.
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After which is certainly fine.
Grammatical, but not fine: the register is too high for the context.