Since Numbers 23:19 states explicitly that "God is not a man, that he should lie", the biblical idea of "lie" must be defined in such a way as to permit the behavior observed here in Exodus.Much of those apologetics boils down to the above, which sounds to me far too much like determining what the definition of "is" is. The author starts with a premise (God doesn't lie) and must make the text reflect that premise instead of reading the text itself.
It states we must view the lies in context, in that they may have been done for the greater good (hello situational ethics). Okay, in Exodus, God had hardened Pharaoh's heart to make him refuse in the first place, and hardened it again several times after Pharaoh had agreed following a plague. If God can harden a heart, he can soften it too, to make him agree to letting them go without resorting to lies.