TLDR;

1. The TLS handshake involves a step to discover the commonly supported algorithms and can incur additional roundtrip if the first guess does not works out, its part of the protocol to keep it stateless

2. Cloudflare is scanning all the origins on daily basis and storing the result for supported algorithms to save on the possible roundtrip time

Whats missing in the article - They are saving on the *possible roundtrip latency, however they are not sharing the absolute lookup latency which now gets added to every connection