Sorry I have only just picked up on this topic. Yes, 1991 was the last year these race report cards were produced. Race reports of a similar style were published in the Club Team Lotus monthly newsletter/magazine, called 'Lotus World', which included news from Team Lotus and Lotus Cars. In early 1990, Lotus Cars withdrew funding for the magazine and 'Lotus World' ceased. However Team Lotus continued to publish the race reports in the race card format, for club members, now known as Team Lotus Associates. Obviously 1991 was a financially difficult year for the team and there were delays in producing the final set of race cards, which weren't sent out to members until mid 1992. So the team decided not to continue with the supporters club for 1992.
Anyway to get to the point, I still have all my copies of Lotus World from 1982 -1990 and the race cards from 1990-1991. So if there are any that you are missing, I am happy to scan the race reports and send to you, providing it is not considered breach of copyright. If so, then I am sure Classic Team Lotus could help, I think they have these publications in their archive, I've seen them reproduced in books such as 'Ayrton Senna The Team Lotus Years' and 'Remembering Elio', by Cotterie Press.
I always found Team Lotus to be helpful, as a youngster I wrote a couple of letters, addressed to Colin Chapman, of course, asking for information and I always received a reply. On one occasion I had asked about F1 car design, in particular ground effect and someone had gone to the trouble of photo copying some information. It was sent with a typed letter on JPS headed paper, which also invited me to join Club Team Lotus, which by chance was just being formed. I was late sending off the application form, so I missed the first issue of Lotus World. I was lucky enough to meet Clive Chapman on a tour of Classic Team Lotus, a couple of years ago and he seems a genuinely nice man. So if your producing a book, I am sure that they would show an interest.