Estimating lognormal parameters from a truncated empirical distribution

I have a set of 50 values that I assume are part of a longnormal distribution. However, the values I have are a biased sample, in the sense that they are all under 1,000. (In other words, I do not have any information on how many values could or should exceed 1,000, or what those values may be.)

I know that if I had a "full sample" I could calculate the mean and variance of my sample and back into the relevant mu and sigma parameters, but is there a way to estimate the full distribution's mu and sigma parameters using some kind of limited expected value and limited variance function?

Thanks in advance!

- Steve J