The bike has a alot of good things going for it. Ishiwata triple-butted 4130 for starters. Don't know how to explain the fork. Maybe it was a replacement as you suggested?
The paint is overall in decent shape, could use some minor touchup. The components, can't say, but they look decent. Always take a pic from the bike's drive-side so that we can view the crankset and the derailers, helps to nail down the group and the range of dates of manufacture.
I am going out on a limb and suggesting that the frame might have been made by Giant or similar for Lotus. I only say that because of the triathlon graphics. Looks similar to ones I have seen on Giant's triathlon bikes.
Looks nice, clean it up, lube it and ride!