IIRC, the Lotus is Ishiwata triple butted tubing, and a Tange Mangalloy fork. The headset is a nice Tange model. Did your's come with a 'Lotus' rubber top cover? If the races and cups are good, just re-ball them.
It's a decent unit.

If you got a pair of Sansin hubs plus Araya rims, the hubs are Sansin Sealed System. Also nice quality.
The rims I think are single-walled seamless. I had a Lotus trash bin bike that I stripped and recall such wheels. Too bad the bike wasn't close to my size, all it had was some rusty nicks and a twisted handlebar from a fall. I remember the group was Shimano Light Action and was SIS 6spd.

Lotuses are nice bikes, looking forward to pics of the completed build.