The delay has already cost Boullier the services of Kimi Raikkonen, and now it is delaying his decision when it comes to appointing a replacement.
Nico Hulkenberg and Felipe Massa are the names in the frame but the duo are waiting for Lotus to conclude complex negotiations with Infinity Racing - a private group of investors from America and Abu Dhabi - with regard to a 35 per cent stake in the team.
With the finances from such a deal in place, and with Lotus trying to also negotiate a sponsorship package with engine supplier Renault, Boullier will finally be in a position to sign a new driver.
"We want to now close this Infinity partner story because this should give us the ability to at least be secure and move us on to the next step," said Boullier, speaking to Press Association Sport in the Suzuka paddock ahead of this weekend's Japanese Grand Prix.
"So there is this part and also a big sponsorship part which is being discussed, and I think we are nearly there. Once we have done this we can afford to pick the driver we want.
"That is why our decision is taking so long."
With Lotus' financial future in limbo, they have lost two key staff members in James Allison and Dirk de Beer - former technical director and head of aerodynamics respectively - to Ferrari, while others are known to be circulating their CVs to other teams.
The conclusion of the Infinity deal is now paramount for Boullier but, when asked about losing more personnel, the Frenchman said: "If you buy a house and you do your mortgage, you're not going to spend more before you sign anything.
"With this process we need to close the deal. It could be tomorrow, it could be next week, but... I will not bring Nico here if we see we cannot afford him."
Boullier has made clear no one within the team is owed any money as Raikkonen claimed one of his reasons for joining Ferrari was due to the fact he had not received part of his salary, believed to be bonuses.
"Everybody has been paid. You can ask anyone in our company," said Boullier.
"Of course, until we can speak with facts about the future of this company some people get nervous, so I'm sure some CVs are circulating in the paddock.
"But at the same time I keep them informed nearly every week. I speak to everyone in the factory. They know exactly where we are, and they know I'm not lying.
"I'm waiting for facts now to go to the next step and make the big announcement."
That also includes Renault as Lotus are the only team in Formula 1 that has yet to sign a new deal with a powertrain supplier for next season.
That particular deal is, however, complicated by the fact Lotus are eager for a sponsorship tie up.
"We would like to discuss a branding opportunity with them and maybe something even closer," added Boullier.
"Everything is ready to be signed (for the engine), everything is the same as Red Bull (who also use Renault engines). I am just waiting a little bit to ensure no stone is left unturned."
There remains the prospect of Boullier signing a pay driver, but he concedes he does not "want to go down that path".
"This is not the way to go," insisted Boullier.
"We are here to compete at the highest level and the ambition of the team and owners is to compete at the highest level.
"So even if we don't have the same means and resource as Red Bull and others, we still can keep going up."
Hulkenberg has made clear he would like "clarification or certainty by the end of October" so if he does not sign for Lotus then he can look elsewhere.
Massa is in the same situation as he said: "I believe the end of October is a good timeframe to have an idea of where I'm going to be next year.
"I don't think it's going to be long until we hear something. It's hard to be specific, but it won't take long.
"Things have progressed for the past few weeks. I still want to wait until they are more definite, but they are definitely progressing."