We love because he first loved us. (1 John 4:19).
Since loving God is the evidence that he loves you with electing love (Romans 8:28, etc.), the assurance that God loves you with electing love cannot be the ground of your love for him. Our love for him, which is the evidence of our election, is our spiritually apprehending the all-satisfying glory of this God.
It is not first gratitude for a benefit received, but recognition and delight that to receive him would produce overwhelming gratitude. This recognition and delight is, or should be, according to Scripture, attended immediately with the assurance that he does in fact give himself to us for eternal enjoyment.
The gospel call (Christ died for sinners; believe on him and you will be saved) is a call not first to believe that he died for your sins but that, because he is the kind of God who redeems at such a cost and with such wisdom and holiness, he is worthy of trust and he is a truly satisfying repose for all my longings.
Believing (that is sensing, apprehending) this is then immediately attended with the confidence that we are saved and that he did die for us, since the promise of salvation is given to those who thus believe.
The core of Christian Hedonism is thus at the very heart of what saving faith is and what it means to truly "receive" Christ, or to love God.
Compare: "We love because he first loved us" (1 John 4:19). This may mean that God’s love enables our love for him through the incarnation and atonement and work of the Holy Spirit, not that our motive to love is first his making much of us.
Or it may mean that in beholding and spiritually apprehending God to be the kind of God who loves sinners like us with such amazingly free grace and through such stunningly wise and sacrificial means of atonement, we are drawn out to delight in this God for who he is in himself, rather than taking the sentence to mean that we love him first because we find ourselves personally and particularly chosen by him.