There's a parable printed in the official LDS (Mormon) teaching manual, Gospel Principles, that illustrates well the difference between our view of the atonement and the LDS view, and it can be helpful in clarifying that difference with your LDS friends.
In this parable (pp. 75-77), originally told by Elder Boyd K. Packer (of the Quorum of the Twelve Apostles), a man finds himself in debt so deep that repayment is impossible. As he's about to be thrown into prison by his creditor, he cries for mercy, but the creditor demands justice. The narrator tells us:
Is there no way for justice to be fully served, and mercy also? There is a way! The law of justice can be fully satisfied and mercy can be fully extended--but it takes someone else. And so it happened this time.
The debtor had a friend. He came to help....He thought him foolish to have gotten himself into such a predicament. Nevertheless, he wanted to help because he loved him. He stepped between them, faced the creditor, and made this offer.
"I will pay the debt if you will free the debtor from his contract so that he may keep his possessions and not go to prison...You demanded justice. Though he cannot pay you, I will do so. You will have been justly dealt with and can ask no more."
So far, this is a familiar story to us. But while we expect it to end here with the gratefulness of the debtor, the LDS story goes on:
The mediator turned then to the debtor. "If I pay your debt, will you accept me as your creditor?"
"Oh yes, yes...You saved me from prison and show mercy to me."
"Then," said the benefactor, "you will pay the debt to me and I will set the terms. It will not be easy, but it will be possible. I will provide a way. You need not go to prison."
The debtor is still a debtor who must still pay. However, Jesus is now the one he must pay back, according to his new terms which require a different payment as an alternative to the previously required payment of spiritual death. For LDS people, Jesus has made our debt manageable by creating a new payment plan:
Our sins are our spiritual debts. Without Jesus Christ, who is our Savior and Mediator, we would all pay for our sins by suffering spiritual death. But because of him, if we will keep his terms, which are to repent and keep his commandments, we may return to live with our Heavenly Father.
It is wonderful that Christ has provided us a way to be healed from our sins.
In other words, Christ has provided the way for us to follow; He, Himself, is not the way. He made forgiveness possible "if we do our part" (p. 75); He has not secured our forgiveness. By contrast, Greg wrote about the biblical view of the atonement using two extremely moving illustrations in the second half of the March/April 2004 Solid Ground. The difference is profound and life-altering.